1,959 research outputs found
Transport in three-dimensional topological insulators: theory and experiment
This article reviews recent theoretical and experimental work on transport
due to the surface states of three-dimensional topological insulators. The
theoretical focus is on longitudinal transport in the presence of an electric
field, including Boltzmann transport, quantum corrections and weak
localization, as well as longitudinal and Hall transport in the presence of
both electric and magnetic fields and/or magnetizations. Special attention is
paid to transport at finite doping, to the -Berry phase, which leads to
the absence of backscattering, Klein tunneling and half-quantized Hall
response. Signatures of surface states in ordinary transport and
magnetotransport are clearly identified. The review also covers transport
experiments of the past years, reviewing the initial obscuring of surface
transport by bulk transport, and the way transport due to the surface states
has increasingly been identified experimentally. Current and likely future
experimental challenges are given prominence and the current status of the
field is assessed.Comment: Review article to appear in Physica
Weak localization in ferromagnets with spin-orbit interaction
Weak localization corrections to conductivity of ferromagnetic systems are
studied theoretically in the case when spin-orbit interaction plays a
significant role. Two cases are analyzed in detail: (i) the case when the
spin-orbit interaction is due to scattering from impurities, and (ii) the case
when the spin-orbit interaction results from reduced dimensionality of the
system and is of the Bychkov-Rashba type. Results of the analysis show that the
localization corrections to conductivity of ferromagnetic metals lead to a
negative magnetoresistance -- also in the presence of the spin-orbit
scattering. Positive magnetoresistance due to weak antilocalization, typical of
nonmagnetic systems, does not occur in ferromagnetic systems. In the case of
two-dimensional ferromagnets, the quantum corrections depend on the
magnetization orientation with respect to the plane of the system.Comment: 14 pages with 10 figures, corrected and extended version, Sec.7 adde
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